When viewers last saw Deathstroke in Season Two of Arrow, Oliver Queen had locked him away in an ARGUS prison on the secluded island of Lian Yu. Neither the show’s cast or crew has revealed exactly how Slade would return to Arrow, or if he would don his Deathstroke guise. And how exactly did Deathstroke escapes his prison cell on Lian Yu remains a mystery.

The show frequently features flashback sequences, so it’s possible that Slade will only return through the past. Either way, the show has plenty to tackle before Slade's return--like how Oliver Queen will rise from his apparent death at Ra's al Ghul's hands.

It will also be kinda interesting to see how a mirakuru-free Slade Wilson interacts with Oliver (Stephen Amell). It'll be interesting to see mirakuru-free Deathstroke fight Ollie (That's if they do fight. He could return in a flashback. Or maybe he'll Slade will realize that Oliver was simply in a no-win situation). Oh and whats going on with with Captain Boomerang if he did escape!